Heating Value Research Articles

The Influence of Rice Husks, Coconut Shells, and Sugarcane Bagasse on the Quality of Bio Briquettes

Coal is a limited natural resource and is found in certain geological locations. Indonesia has abundant mineral and coal resources, with fairly good quality and quantity. The use of coal as fuel has an impact on the environment because CO2 emissions resulting from burning coal can cause a greenhouse effect. One solution to the problem of using coal is the production of alternative energy in the form of briquettes from biomass. This research aims to study the effect of adding a mixture of bagasse, rice husks and coconut shells on the calorific value. The carbon and hydrogen content in biomass greatly influences the water content of the briquettes produced. The increase in carbon content is generally inversely proportional to water content. Briquettes from coconut shell biomass have a higher carbon content than those from rice husks and sugar cane bagasse. The highest calorific value was obtained from coconut shell biomass briquettes, namely 5280.85 cal/g, because briquettes from coconut shells had the highest carbon content, namely 57.18% compared to the carbon content of rice husks and sugar cane bagasse, namely 37 respectively. 24 and 50.04%. Carbon is one of the main components that influences the energy value of briquettes. Although the hydrogen content also contributes to the heating value, its impact is not as big as the carbon content in biomass. The elemental composition of CHNS can affect the water content and calorific value produced. Briquettes from this biomass are only suitable for use as fuel for household purposes.

Experimental Investigation of Ammonia/Oxygen/Argon Combustion: The Role of Equivalence Ratio and Nozzle Shape in a Constant Volume Combustion Chamber with Sub-chamber

The global rise in carbon emissions presents a rising challenge for current and future generations. In the pursuit of zero carbon emissions, ammonia (NH3) has emerged as an attractive alternative energy source. Ammonia offers a carbon-free fuel option with a higher energy density than liquid hydrogen while maintaining ease of transport and storage. However, ammonia still has its drawbacks, such as a high autoignition temperature, slow burning velocity, and low heating value, that demand further investigation of its combustion characteristics. This experiment was done to study the effect of nozzle shape and equivalence ratio (ɸ) on the combustion of an ammonia/oxygen/argon mixture using a constant volume combustor equipped with a sub-chamber. The fuels were premixed for 10 minutes and conditioned to an initial pressure of 0.2 MPa and an initial mixture temperature of 423 K. The results show that the different nozzle shapes each have their advantages in terms of pressure and jet speed. Overall, the lean mixtures (ɸ0.6 and ɸ0.8) consistently performed better compared to the stoichiometric mixtures (ɸ1.0) in all categories investigated in this study. The round nozzle generates higher pressure, while the special shape nozzle enhances jet speed, highlighting trade-offs between the two.

Study of municipal solid waste treatment using plasma gasification by application of Aspen Plus

Abstract Plasma gasification is a viable and efficient technique for handling solid waste, including hazardous waste, while also holding the potential for energy recovery. The objective of this study is to analyze the treatment of municipal solid waste (MSW) using plasma gasification by application of Aspen Plus software. An earlier proposed model was used to analyze the effect of employing different types of gasifying agents as plasma gas, on the composition of syngas produced. The lower heating value, cold gasification efficiency and carbon conversion efficiency were calculated and compared in each case. A sensitivity analysis study was also carried out to observe the effect of variation in plasma gas flow rate and feed flow rate on the composition of syngas generated. The capital, operational and maintenance costs of the process were determined using existing correlations. For a feed rate of 20,000 kg per hour of MSW, the highest yield of syngas (CO (33.48 %), and H2 (34.30 %) with the highest LHV (7.9 MJ/N-m3)) were produced when air was employed as plasma gas. The cold gas efficiency and the carbon conversion efficiency were at their peak when air was used as the gasifying agent. The sensitivity analysis revealed that as the flow rate of plasma gas increases syngas production decreases while the increase in MSW flow rate results in an increase in syngas production. Additionally, the cost analysis revealed that for a plasma gasification plant that can handle 500 tons of MSW per day, the estimated capital and annual operational and maintenance costs are $125,496,721 and $9,833,892 respectively.

Optimization of waste biomass demineralization through response surface methodology and enhancement of thermochemical and fusion properties

This study examines the impact of leaching with dilute hydrochloric acid solution on the reduction of ash content and the thermal degradation behavior of sugarcane bagasse. Response surface methodology (RSM) was used to statistically design the experiments and investigate the effect of three independent variables: treatment time, solid-to-liquid ratio, and reagent concentration. The leaching conditions were further optimized and experimentally validated for maximum ash reduction for suitability of treated biomass as feedstock for thermochemical conversion technologies. Reagent concentration and treatment time directly affected ash reduction, while the solid-to-liquid ratio inversely influenced it. Concentration had the highest impact, and treatment duration had the least. The maximum 78.2% ash reduction was achieved by treating the biomass with 1 M HCl for 80 min at a solid-to-liquid ratio of 50:1 (wt/vol). This ash reduction also resulted in a 9.82% increase in higher heating value (HHV). Hemicellulose hydrolysis during leaching was observed through chemical composition and Fourier-transform infrared spectroscopy (FTIR). Ash fusion temperatures increased, indicating more thermally stable biomass. Thermogravimetric analysis (TGA) showed elevated maximum degradation temperature and activation energy.

Acid-catalyzed co-hydrothermal carbonization of sewage sludge and mixed straws to produce high-quality solid fuel

To improve the hydrochar fuel quality, acid-catalyzed co-hydrothermal carbonization (co-HTC) of sewage sludge with mixed straws were performed at 220 °C. The impacts of mixing ratio (1:0, 1:3, 1:1, 3:1, and 0:1) and solvent (0.5 M HCl or dionized water) on hydrochar quality were assessed. The acid-catalyzed co-HTC increased the higher heating value and fuel ratio of the hydrochar by decreasing the H/C atomic ratio and increasing the O/C atomic ratio. The devolatilization index (Di) and combustibility index (S) of the hydrochar from co-HTC at a sludge-to-straws dry-mass ratio of 1:1 reached 64.6 and 26.8 (10−8 wt%2 min−2 K−3), respectively, which was over three times and 2.5 times that from sludge. Di was affected by the surface functional groups, whereas S was related to the chemical composition and fuel properties. Less energy is required after acid-catalyzed co-HTC for both pyrolysis and combustion processes, because of the increase in O/C atomic ratio. This study not only demonstrates the yields and quality of the hydrochar in response to the variation of mixing ratio and solvent, but also uncovers the relationship between hydrochar quality and pyrolysis/combustion performance, thereby providing valuable information for optimizing the acid-catalyzed co-HTC process.

Efficient High Heating Value estimation using Latin Hypercube Sampling and Artificial Neural Network-based approach.

To maximize energy recovery in waste-to-energy (WTE) systems, the High Heating Value (HHV) of municipal solid waste (MSW) must be accurately estimated. To forecast the HHV of MSW, this study proposes a unique method that combines an Artificial Neural Network (ANN) model with Latin Hypercube Sampling (LHS), with a focus on Solan City, Himachal Pradesh, India. In the present study, the elemental characteristics of waste have been used to deal with uncertainty and to find the suitable parameters responsible for the HHV of the MSW. Initially, Latin Hypercube Sampling (LHS) has been used to deal with uncertainty in the elemental composition of MSW, which includes carbon (C), hydrogen (H), nitrogen (N), sulfur (S), and oxygen (O) content. This elemental composition has been used as input parameters to the ANN model for predicting the HHV of MSW. The network 5-28-5-1 offered a minimum MAPE value of 2.18%, MSE, RMSE and R2 values are 0.012, 0.107 and 0.767, respectively. Thereafter, a synaptic weight approach was used to find the most significant parameters responsible for HHV in MSW. It was observed that carbon is the most suitable parameter for HHV of MSW. By dealing with the uncertainty in MSW characteristics, the integration of LHS strengthens the robustness of the model. The results offer an accurate and economical approach for HHV estimation, which will be useful for improving the MSW management and WTE conversion procedures.

Carbonization of Refuse-Derived Fuel Pellets with Biomass Incorporation to Solid Fuel Production

In this work, dry carbonization (DC) and hydrothermal carbonization (HTC) of refuse-derived fuel (RDF) pellets were conducted to evaluate the physical, chemical, and fuel properties of the produced chars. In the dry carbonization tests, biomass sawdust was incorporated in different proportions on the samples to minimize agglomeration caused by the melting of the plastic fraction. The experiments were carried out in a temperature of 400 °C (DC) and 250–300 °C (HTC), in a residence time of 30 min. The respective chars and hydrochars were characterized according to their mass yield, apparent density, proximate, elemental, and mineral composition, chlorine content, high heating value, thermogravimetric profile, and surface functional groups. The results showed that the dry carbonization of RDF pellets with biomass incorporation, followed by a washing step, resulted in the production of chars with improved properties such as higher fixed carbon and higher heating value (HHV) (25–26 MJ/kg) and lower ash and chlorine content. Additionally, the HTC experiments demonstrated that hydrochars showed improved properties without the need for biomass addition and washing, however, with no significant difference in the HHV (20–21 MJ/kg). Therefore, DC of RDF pellets with 10% biomass incorporation seems to be a promising option to overcome the constraints of RDF utilization as an alternative fuel.

Reaction kinetics and isotherms of commercial activated carbon in variable pressure adsorption of high compound VOCs

ABSTRACT This study investigated the feasibility of using/reusing commercial activated carbon (CAC) for the capture of high molecular weight and high-boiling point volatile organic compounds (HBPVOCs). The CAC was first characterized using proximate analysis, heat value analysis, iodine value analysis, element analysis, inductively coupled plasma spectrometry, and specific surface area analysis. We then assessed the adsorption/desorption performance of a CAC-based PSA system for the removal of Butyl Cellosolve (BCS), a HBPVOC commonly used in paints, coatings, cleaners, and industrial processes. This involved deriving the BCS adsorption capacity of CAC as a function of adsorbent quantity (2.5, 5, and 10 g), flow rate (4, 6, and 8 L/min), and pressure (1.3, 2.3, and 3.4 kg/cm2). The BCS adsorption capacity of the CAC varied with pressure as follows: 1.3 kg/cm2 (652.85 mg/g), 2.3 kg/cm2 (817.20 mg/g) and 3.4 kg/cm2 (1324.05 mg/g). The adsorption mode most closely resembled pseudo-first-order kinetics (i.e. single-layer physical adsorption). Desorption was performed using an adjustable tubular high-temperature furnace under a nitrogen atmosphere (0.93 kg/cm2). Following desorption with a set desorption duration of 1 hr, the BET values varied with temperature as follows: 350°C (75.58% of the original value) and 450°C (86.04% of the original). Desorbed CAC (DCAC) was also examined to detect changes in pore structure due to the effects of recycling. We obtained breakthrough curves and adsorption capacity curves of CAC as functions of flow rate and pressure. We also investigated adsorption performance under pressure swing conditions from the perspective of reaction kinetics and density functional theory. Our results demonstrate the efficacy of CAC in the adsorption of BCS as well as the recyclability of this material. Implication Statement This study demonstrates the potential for reusing commercial activated carbon (CAC) to capture high molecular weight and high-boiling point volatile organic compounds (HBPVOCs). Through comprehensive characterization and performance evaluation, we found that CAC effectively adsorbs Butyl Cellosolve (BCS), a common industrial solvent, with adsorption capacity increasing with pressure. The adsorption process follows pseudo-first-order kinetics, indicating single-layer physical adsorption. Additionally, the study highlights the recyclability of CAC, as desorption and subsequent analysis revealed minimal changes in pore structure, maintaining a significant portion of its original BET value. These findings suggest that CAC is not only effective for BCS adsorption but also sustainable for repeated use, offering an efficient and eco-friendly solution for managing industrial HBPVOCs.

Renewable syngas production and technoeconomic validation in a pilot-scale reactor of air and air-steam gasification of biomass

Optimal conditions for the gasification at the pilot scale of pine chips biomass feedstock with two different gasifying agents (air and an air/steam mixture) are determined. Ten experimental tests were performed at a fixed temperature, air stoichiometric ratio, and steam-to-biomass ratio. Results showed cold gas efficiencies circa 75 % (air) and 95 % (air/steam), yielding ∼3 Nm3syngas/kgbiomass, in both cases, and lower heating values of 7.6 and 8.5 MJ/Nm3, respectively. Hydrogen production and process performance were assessed and compared to those found in literature, showing a good performance considering biomass, ca. 35 g H2/kg biomass. A techno-economic model fed with the experimental results obtained was validated. The model established that air gasification could be more profitable for energy than air/steam gasification, especially at higher scales. The internal return rate was less than 1.5 years; nevertheless, air/steam mixture as a gasifying agent more adequate for H2/biofuel production.

Evaluation of char properties from co-pyrolysis of biomass/plastics: effect of different types of plastics

Co-pyrolysis of biomass/plastics is a viable method to obtain high-quality carbon materials. The synergistic effect in the char production process of co-pyrolysis of biomass/plastics affects the properties of the obtained char. However, the synergistic effect research on the char production process of co-pyrolysis of biomass/plastics is facing challenges owing to highly varying composition of different plastics. In this study, the synergistic effect during co-pyrolysis of bamboo (BM) and plastics (polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), polycarbonate (PC), and polybutylene terephthalate (PBT)) was investigated. TG results showed that PP, PS, PET, and PBT promoted the release of biomass volatiles and increased co-pyrolysis char yield. Notably, the O-aromatic structure in PC underwent cleavage and deoxygenation reactions, inhibiting the production of co-pyrolysis char during co-pyrolysis process. Char yield from co-pyrolysis process decreased from 24.80% for bamboo pyrolysis to 15.74% for co-pyrolysis of bamboo/PC. The results of physicochemical tests on char samples indicated that the addition of polyhydrocarbon plastics (PP and PS) increased H/C ratio, O/C ratio, heating value and oxidative reactivity of the char compared to bamboo char due to the vapor deposition of hydrocarbons derived from thermal decomposition of plastics on the biomass char. While, co-pyrolysis of biomass and polyester plastics (PET, PC, PBT) improved the pore structure of char and increased oxygen content.

Spent tea leaves and tea bags - promising biofuels?

The spent tea leaves used after the extraction of liquid from processed tea are insufficiently utilized waste, rich in essential amino acids, polyphenols, alkaloids, and minerals, produced in large quantities, e.g., in tea houses, hospitals, school canteens, etc. Therefore, this study is aimed at characterizing this waste, how it is processed into pellets and how it subsequently increases its energy potential by torrefaction. The influence of the method of tea packaging, i.e., loose tea leaves or tea bags, was also considered. Several types of tea waste were processed using a pilot plant pelletizing press and torrefaction stand. The prepared pellets were characterized by mechanical parameters, such as the pellet durability index, the wettability index, water resistance, hardness, or specific bulk density, and were integrated by FTIR measurements. Furthermore, pellet’s energy parameters, such as higher heating value, lower heating value, and elemental analysis, were compared. The results show that non-torrefied pellets have an average combustion heat of 19 KJ.kg-1, while torrefied pellets have a value of 9 KJ.kg-1 higher. Overall, the study demonstrates that spent tea leaves can be converted into a sustainable source of bioenergy and presents a solution for the treatment of this waste, as well as a renewable energy option.

Enhancing energy release and controlled combustion of B-based MICs by the synergistic effect between polyvinyl pyrrolidone and nitrocellulose

To enhance energy release of boron-based metastable intermixed composites (MICs), a series of B-based MICs were constructed successfully by a facile one-step sol-freeze-drying (SFD) method, where copper oxide (CuO) was employed as oxidant. The structure, morphology, chemical state and specific surface area of B-based MICs were investigated by several characterization technologies, and their reactivity and combustion performance were further studied by various experimental tests. The results reveal that B and CuO nanoparticles were dispersed evenly on a nest network braided by the molecular interaction between polyvinyl pyrrolidone (PVP) and nitrocellulose (NC), and the constant volume combustion heat of B-based MICs even reaches 8956.6 ± 76.6 J·g−1 when PVP (1.25 wt%) and NC (5.0 wt%) were added into B/CuO. The heat value is about 1.7 times as big as pristine B/CuO (5345.5 ± 36.1 J·g−1) and approaches to that of raw B NPs (10335.5 ± 507.8 J·g−1). Moreover, the condensed phase residues of three composites were confirmed to be Cu and Cu2O, while the smallest particle size distribution of product proves that the combustion of B/CuO/NC(NC: 5.0 wt%, PVP: 1.25 wt%) is most complete. So the unique nest network can eliminate particle aggregation, shorten the transfer distance of mass and heat and improve the “solid − solid” thermite reaction. This work will provide a new strategy for promoting the application of boron

The Heat Transfer in Skin Tissues Under The General Two-Temperature Three-Phase-Lag Model of Heat Conduction with a Comparative Study

In this paper, a new and more general model of heat conduction that depends on the drift velocity due to thermomass motion assumption will be established and will be applied to the skin tissue. Four different heat conduction models will be incorporated into a unified equation of heat conduction: the Pennes, Vernotte-Cattaneo, dual-phase-lag of Tzou, and the general two-temperature three-phase-lag of Youssef. The governing partial differential equations of the general two-temperature three-phase-lag model of bioheat conduction will be implemented and solved directly in the domain of the Laplace transformation. The numerical solutions of the Laplace transform will be calculated by executing the Tzou iteration formula. The ramp-type heat on the surface of the skin tissue will be considered as thermal loading. The conductive and dynamic temperature increment reactions have been studied and discussed with different values of ramp-time heat, characteristic length, and drift velocity parameters. The novelty of this work is to introduce some comparisons of the four under-studied bioheat conduction models and show the differences between them in the figures. The numerical results show that the ramp-time heat, drift velocity, and characteristic length parameters have major impacts on the increment of both dynamical and conductive temperature distributions.

Techno-economics of High Ash Coal Gasification: A Machine Learning Approach using CatBoost Model

This work explores the techno-economics of high ash coal gasification using circulating fluidized bed (CFB) gasifier technology at the Talaipalli Coal Mining Project, India being developed by NTPC Limited. The research employs the categorical boosting machine learning algorithm to predict syngas composition, yield, and lower heating value offering an innovative approach to optimize the gasification process. The work compares CFB gasification with conventional coal combustion and establishes it as the most suitable gasification technology due to its feedstock flexibility, technological maturity, and cost-effectiveness. A comprehensive financial analysis reveals a favorable net present value (NPV) of ₹ 20150 Million, an internal rate of return (IRR) of 9.54%, and a payback period of 8.3 years for a 65 MWth CFB gasifier. Sensitivity analysis highlights the influence of key factors such as syngas yield, capital costs, and selling price on financial viability. The environmental benefits, including reduced emissions and waste management, further underscore the value of coal gasification for sustainable energy production. This work aligns with government initiatives like the National Coal Gasification Mission, advocating future research in co-gasification and techno-economic assessments for similar projects.

Bioenergy and bioexergy analyses with artificial intelligence application on combustion of recycled hardwood and softwood wastes

Novel biomass bioenergy-bioexergy analyses via thermogravimetry analysis and artificial intelligence are employed to evaluate the three biofuels from wood wastes (softwood-SW, hardwood-HW, and woods blend-WB). The chemical characterization of SW has the highest bioenergy (higher heating value – HHV: 18.84 MJ·kg-1) and bioexergy (specific chemical bioexergy – SCB: 19.65 MJ·kg-1) with the SCB/HHV ratio of wood waste as about 1.043-1.046. The high C-element has a significant influence on the HHV-SCB. The SCB/HHV ratio of wood waste is recognized as about 1.043-1.046. The three distinct zones of wood waste combustion are identified: moisture evaporation (Zone I, up to 110 °C), combustion reaction – degradation of three major lignocellulosic components (hemicelluloses, cellulose, and lignin) at Zone II, 110-600 °C, and ash remains (Zone III, 600-800 °C). The ignition (Dig=0.01-0.04) and fuel reactivity (Rfuel=3.82-6.97 %·min-1·°C-1) indexes are evaluated. The comprehensive combustion index (Sn:>5×10-7%2·min-2·°C-3) suggests that wood waste has a better combustion performance than bituminous coal. The statistical evaluation presents that the highest HHV-SCB values are obtained by performing combustion for SW-250 μm at 15 °C·min-1. The S/N ratio and ANOVA results agree that the wood waste type and particle size denote the most influential parameters. The artificial neural network prediction shows an excellent result (R2=1) with 1 hidden layer and 5 neuron configurations.

Effect of sludge-based additive on particulate matter emission during the combustion of agricultural biomass pellet

In this study, the effects of a sludge-based additive on particulate matter emission during the cornstalk pellet combustion were investigated using a vertical fixed bed reactor combined with a Dekati low pressure impactor (DLPI). It was found that the PM1 and total PM10 yields from the cornstalk pellet combustion were much higher than those from the individual combustion of sludge-based additive. With the addition of sludge-based additive, the alkali and alkaline earth metals (AAEMs) in biomass would react with the Al/Si-containing and P-containing inorganic minerals in sludge-based additive to form various aluminosilicates, silicates, and K-Ca-P compounds, which could enhance the potassium fixation and retain it in the coarse particles, such as fly ash and residual ash. The PM1 and total PM10 yields from the composite pellet combustion could be effectively reduced by 62%, with the mixing ratio of sludge-based additive increasing to 75%. The mixing ratio of sludge-based additive showed a positive synergistic effect in reducing the emission of PM and a mixing ratio of <30% was recommended based on comprehensive considerations to produce relatively high-quality pellet fuel with respect to good heating value and low ash content and PM emission in later combustion application.

Hydrothermal carbonization of primary sewage sludge in a prototype reactor: Sensitivity analysis of key parameters for hydrochar and liquid phase upscaling and reuse

Hydrothermal carbonization (HTC) of untreated sewage sludge with high water content was evaluated as an alternative to usual wastewater treatment. This bold approach allowed bioproducts useful as biofuel and nutrient sources to be obtained directly from raw sludge. HTC experiments were performed in a scalable arrangement (technology readiness level >4) composed of a 10-liter high-pressure reactor. The influence of the experimental conditions, including temperature (180-220°C), reaction time (60-120min), and pH (6.5-12.0), was evaluated on nutrients and heavy metal distribution through the liquid phase by a 23 central composite design with a triple central point. The bioproducts were characterized by a set of six analytical techniques, and the results were refined by statistical procedures (Principal Component Analysis and Response Surface Methodology). pH is a variable that impacts bioproducts’ characteristics, making it a guiding factor for application. Basic pH promotes transfer of components from solid to liquid phase, while natural pH favors the heating value of hydrochars. Liquid phase is a carbon- and nitrogen-rich source that can be useful for plant nutrition, mainly due to the increase of ammonia nitrogen from 20.6 to 51.7wt.% under pH 6.5, and an expressive decrease of chemical oxygen demand from 32 to 6-16 mgO2L-1. The hydrochar can be considered a renewable solid fuel, reaching up to 12.43 MJ kg-1 under pH 6.5; the basic pH favored an increase in the O/C ratio and lower HHV values. HTC of primary sewage sludge can replace steps of a conventional treatment station and promotes treated wastewater reuse.

Scrupulous analysis of the carbon footprint of sustainable electricity produced from raw bagasse, torrefied bagasse, and filter cake pellets in Thailand

This study evaluates the carbon footprint of a 25 MW biomass power plant in a sugar factory, focusing on its 8 MW grid supply. Six key activities were assessed: fuel preparation, combustion, power generation, particulate removal, and water production (soft and cooling). The research compares greenhouse gas (GHG) emission from three scenarios: 100 % raw bagasse (RB), RB mixed with torrefied bagasse (TB), and RB with filter cake pellets (FP) at ratios of 95:5, 97:3, and 99:1. Data collected throughout 2023 revealed that the plant consumed 119,769.89 tons of RB (51 % moisture, 7740.40 kJ/kg heating value), generating 31,552,711.00 kWh annually. Emissions were calculated in kg CO2eq/kWh using the 2006 IPCC Guideline (The Intergovernmental Panel on Climate Change). Results showed that 100 % RB emitted (0.184+0.006, −0.005) kg CO2eq/kWh. Incorporating TB reduced emissions to 5 % = (0.178±0.005), 3 % = (0.178+0.006, −0.005) and 1 % = (0.178+0.006, −0.005) kg CO2eq/kWh due to decreased diesel oil, electricity, and steam usage in fuel preparation. Remarkably, using FP further decreased emissions, with 5 % FP resulting in negative total GHG emissions of (-0.225+0.015, −0.017) kg CO2eq/kWh, primarily due to the FP preparation process (-15,096,234.40±56,716.07 kg CO2eq/year). The study concludes that combining RB with TB or FP significantly reduces emissions and increases electricity production 5 % torrefied bagasse decreased 0.30 %, 3 % torrefied bagasse decreased 1.34 % and 1 % torrefied bagasse decreased 2.41 %, 5 % pelletized filter cake decreased 229.95 %, 3 % pelletized filter cake decreased 139.77 % and 1 % pelletized filter cake decreased 48.77 % by compare raw bagasse 100 %, promoting sustainable energy generation. These findings encourage the use of biomass for sustainable and environmentally advantageous power production.

Thermogravimetric Assessment of Biomass: Unravelling Kinetic, Chemical Composition and Combustion Profiles

Thermogravimetric analysis (TGA) was performed on six samples of pine wood, poplar sawdust and olive residue, and the kinetic parameters were evaluated by using isoconversional models. The hemicellulose, cellulose and lignin contents were also estimated using the Fraser–Suzuki deconvolution method. In addition, a range of thermodynamic parameters and combustion indices was calculated. Significant correlations were found between the kinetic, thermodynamic and combustion parameters. The ignition index showed an inverse relationship with the activation energy, whereas the burnout index correlated with enthalpy values for most samples. Higher heating rates during TGA increased ignition and combustion efficiencies but decreased combustion stability. Differences in behaviour were detected between the olive residues, which had a much higher lignin content (51.2–56.9%), and the woody biomass samples (24.2–29.2%). Moreover, the sample with the highest ash content also exhibited some distinctive characteristics, including the lowest high heating value and ignition index, coupled with the highest activation energy, indicating a less favourable combustion behaviour than the other samples. The particle size of the samples was also found to be critical for both combustion efficiency and safety.

Thermal engineering and chemical kinetics of wood pellets torrefication

Relevance. The widespread distribution and availability of biomass in the regions of Russian Federation make it possible to consider it as a renewable energy source with a lower negative impact on the environment compared to fossil fuels, since biomass is recognized as a carbon-neutral fuel. The use of biomass as a fuel in the form of pellets is increasing, which provides increased density and heat value. At the same time, pellets as a fuel or as a technological raw material have a significant disadvantage – low hydrophobicity. This problem is solved by torrefaction – low-temperature pyrolysis at a temperature of 200–300°C to produce bio-carbon. The study of the wood pellets torrefaction in order to improve it is an urgent task. Aim. To identify the impact of the parameters of the torrefaction of wood pellets on the thermal characteristics of the product (the highest heat value of bio-coal) and the regime parameters of the process (mass and energy yields), as well as to determine the parameters of the chemical kinetics of low-temperature pyrolysis as the basis for mathematical modeling and development of efficient torrefaction reactors. Object. Torrefied coniferous wood pellets of domestic production (Moscow region). Methods. Experimental study of the low-temperature pyrolysis thermal characteristics; synchronous thermal analysis in an inert atmosphere. Results. It was found that during the torrefaction of wood pellets in an inert atmosphere, a change in the holding time in the range of 30–60 minutes does not significantly affect the higher heat value, mass and energy yield of bio-coal, while an increase in temperature from 250 to 300°C reduces mass and energy yield, and the higher heat value increases by 26%. The dynamics of mass loss and thermal effects when heated to 600°C at a rate of 10 K/min are determined by means of the synchronous thermal analysis. It is established that the chemical kinetics of the process is described by a generalized reaction of the order n=1.507, in the Arrhenius equation the activation energy E=71.25 kJ/mol, the pre-exponential factor A=4772 s–1.